Questions tagged [ctr]
Counter Mode (CTR) is an encryption mode, that builds a random-access stream-cipher from a block-cipher.
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Parallel block cipher in CTR mode and variable number of threads: how to deal with internal state and permit decryption?
I'm implementing a parallel block cipher (Morus, to be precise) in CTR mode and I'd like to make it flexible with respect to the number of threads. It is not difficult per se, as I can partition the ...
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Is AES-CTR mode with predictable IV vulnerable to CPA attacks?
I'm just confused about this topic problem.
I know that the CBC mode will be vulnerable to CPA attacks if the IV is predictable, but what about the CTR mode?
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Encrypting the nonce in AES-CCM
I'm working on a network where nodes communicate using AES-CCM encryption, within a context of tight bandwidth limitations, making every bit count. The setup uses a nonce that combines a 16-bit node ...
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Exposing the vulnerability of CTR mode of operation
In the CTR mode of operation, the plaintext block is treated as a stream cipher, where each byte of the plaintext gets XOR-ed with each byte of the key (which is generated using a nonce and a counter) ...
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What input parameters can be made public in the AES-CTR mode?
Preface: I am beginner of cryptography and not native English speaker. So I may make terrible mistake (about grammar and cryptography).
I understand that the parameters used for AES-CTR are "key&...
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Using a hash instead of AES-CTR before XORing a plaintext [duplicate]
In AES-CTR, a key, a nonce and a counter are all encrypted to produce a value that is then XORed with a plaintext to produce the ciphertext.
Let's say we were to make a hash out of the key, the nonce ...
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How weak is using AES with a 128 bit key but 64 bits of the secret key are public constants?
Respected community,
I was wondering how weak would AES-128 be, if we provide only a 64 bit key with the other remaining 64 bits either zero bits or public constants, known to the attacker.
Is it easy ...
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Key expansion in AES CTR mode
While working with AES 256 in CBC mode, I learned that it requires Key Expansion - forward (for encryption) and reverse (for decryption).
Does AES CTR mode also requires such a step ? Or can the 256 ...
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Encrypting random IV in CTR mode (no nonce!)
Use of plain random-IV's in CTR mode, without any special "nonces/counters" (or any "dedicated" bits!), can lead to problems with "partial overlaps", whereby attackers ...
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How CTR mode is encrypted?
I referred to the explanation of encryption mode from Wikipedia, but I'm confused now, and I went to find some books about Cryptography, but it didn't solve my confusion.
The CTR mode uses Counter to ...
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If encrypting with a hash function in counter mode, will the security of this scheme be at most minimal{input,output}?
It's possible to use a hash function as an encipherment scheme if used in counter mode.
Let's suppose I take a 64-bytes (512-bits) seed/key and hash it concatenated with counters, and use it as a ...
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Is a naive 27bit FPE algorithm using AES-CTR insecure?
I don't have a deep mathematical background in cryptography. I am reading "The FFX Mode of Operation for Format-Preserving Encryption". Section D says the following.
Why feistel? The ...
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In CTR block cipher mode of operation, can I reuse the nonce with another key for encrypting another plaintext if using different counters?
Let's suppose I encrypt a plaintext with one key and a nonce in CTR block cipher mode of operation.
Can I reuse the nonce with another key in another plaintext if I start the block counting with ...
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Clarification regarding AES-CTR
I was recently trying to perform a AES-128 CTR Encryption and Decryption.
I had a observation that if a AES-CTR encrypted value is encrypted again (with same key and Iv) it results in the plain text ...
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When the input size in a PRF is larger than the output and many inputs will generate the same output, but why AES-256 in CTR mode is considered safe?
I know that if the input size in a pseurandom-function is larger than its output, many different inputs will generate the same output by the Pigeonhole principle (I also read an article related to ...
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